<style>
  .btn {
    border-radius: 5px;
    background-color: #4f73e8;
    border: #4f73e8;
    opacity: 1;
    transition: 0.3s;
  }

  .btn:hover {
    background-color: #2144b6;
    border: #2144b6;
  }
</style>


<a href="https://leanpub.com/introductiontozigaproject-basedbook">
    <button class="btn btn-primary" type="button">
	Buy the book on Leanpub!
    </button>
</a>
